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feat(websub): Add websub controller and helper methods (#8014)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,192 @@ | ||
| import { Response, Request } from 'express' | ||
| import { networks } from '@unlock-protocol/networks' | ||
| import * as z from 'zod' | ||
| import fetch from 'cross-fetch' | ||
| import crypto from 'crypto' | ||
| import html from 'html-template-tag' | ||
| import logger from '../logger' | ||
| import { Hook } from '../models' | ||
|
|
||
| const Hub = z.object({ | ||
| topic: z.string().url(), | ||
| callback: z.string().url(), | ||
| mode: z.enum(['subscribe', 'unsubscribe']), | ||
| lease_seconds: z.number().optional(), | ||
| secret: z.string().optional(), | ||
| }) | ||
|
|
||
| const EXPIRATION_SECONDS_LIMIT = 86400 * 90 | ||
|
|
||
| export function getExpiration(leaseSeconds?: number) { | ||
| const limit = leaseSeconds ?? 864000 | ||
| if (limit > EXPIRATION_SECONDS_LIMIT) { | ||
| throw new Error("Lease seconds can't be greater than 90 days") | ||
| } | ||
| return new Date(Date.now() + limit * 1000) | ||
| } | ||
|
|
||
| export async function subscribe( | ||
| hub: z.infer<typeof Hub>, | ||
| params: Record<string, string> | ||
| ) { | ||
| try { | ||
| const hook = await Hook.findOne({ | ||
| where: { | ||
| topic: hub.topic, | ||
| callback: hub.callback, | ||
| }, | ||
| }) | ||
|
|
||
| if (!hook) { | ||
| await validHubIntent(hub) | ||
|
|
||
| const expiration = getExpiration(hub.lease_seconds) | ||
|
|
||
| const createdHook = await Hook.create({ | ||
| expiration, | ||
| topic: hub.topic, | ||
| callback: hub.callback, | ||
| mode: hub.mode, | ||
| secret: hub.secret, | ||
| network: params.network, | ||
| lock: params.lock, | ||
| }) | ||
|
|
||
| return createdHook | ||
| } | ||
|
|
||
| if (hook.mode !== hub.mode) { | ||
| hook.mode = hub.mode | ||
| } | ||
|
|
||
| if (hub.lease_seconds) { | ||
| hook.expiration = getExpiration(hub.lease_seconds) | ||
| } | ||
|
|
||
| if (hub.secret) { | ||
| hook.secret = hub.secret | ||
| } | ||
|
|
||
| await validHubIntent(hub) | ||
|
|
||
| await hook.save() | ||
| return hook | ||
| } catch (error) { | ||
| logger.error(error.message) | ||
| return error | ||
| } | ||
| } | ||
|
|
||
| // Check if the subscriber request is valid or not. This will post a challenge to subscriber to confirm the intent of the request. | ||
| export async function validHubIntent(hub: z.infer<typeof Hub>) { | ||
| const challenge = crypto.randomBytes(20).toString('hex') | ||
| const result = await fetch(hub.callback, { | ||
| method: 'POST', | ||
| headers: { | ||
| 'Content-Type': 'application/json', | ||
| }, | ||
| body: JSON.stringify({ | ||
| hub: { | ||
| ...hub, | ||
| challenge, | ||
| }, | ||
| }), | ||
| }) | ||
|
|
||
| const json = await result.json() | ||
|
|
||
| if (!result.ok) { | ||
| throw new Error("Subscriber didn't confirm intent.") | ||
| } | ||
|
|
||
| if (json.challenge !== challenge) { | ||
| throw new Error('Challenge did not match') | ||
| } | ||
|
|
||
| if (json.topic !== hub.topic) { | ||
| throw new Error('Topic did not match') | ||
| } | ||
|
|
||
| if (json.callback !== hub.callback) { | ||
| throw new Error('Callback did not match') | ||
| } | ||
|
|
||
| return hub | ||
| } | ||
|
|
||
| export function getSupportedNetwork(network: string) { | ||
| if (!networks[network]) { | ||
| logger.error(`Unsupported network: ${network}`) | ||
| return | ||
| } | ||
| return networks[network] | ||
| } | ||
|
|
||
| export async function subscriptionHandler(req: Request, res: Response) { | ||
| try { | ||
| // We check the hub schema here to make sure the subscriber is sending us the correct data. | ||
| const hub = await Hub.parseAsync(req.body.hub) | ||
| // We check the network here to make sure the subscriber is sending to the right network endpoint. | ||
| const network = getSupportedNetwork(req.params.network) | ||
| if (!network) { | ||
| return res.status(400).send('Unsupported network') | ||
| } | ||
| // We send the accepted request to the subscriber and then validate the intent of the subscriber as well as persist the subscription. | ||
| res.status(202).send('Accepted') | ||
| return subscribe(hub, req.params) | ||
| } catch (error) { | ||
| logger.error(error.message) | ||
| // We respond with the error if we cannot subscribe or there is an error in the subscriber request. | ||
| return res.status(500).send({ | ||
| hub: { | ||
| mode: req.body.hub.mode, | ||
| topic: req.body.hub.topic, | ||
| reason: error.message, | ||
| }, | ||
| }) | ||
| } | ||
| } | ||
|
|
||
| export function publisherHandler(req: Request, res: Response) { | ||
| try { | ||
| const network = getSupportedNetwork(req.params.network) | ||
| if (!network) { | ||
| return res.status(400).send('Unsupported network') | ||
| } | ||
|
|
||
| const url = new URL(req.originalUrl, `${req.protocol}://${req.hostname}`) | ||
| const links = [ | ||
| { | ||
| rel: 'self', | ||
| href: url.toString(), | ||
| }, | ||
| { | ||
| rel: 'hub', | ||
| href: url.toString(), | ||
| }, | ||
| ] | ||
| res.setHeader( | ||
| 'Link', | ||
| links.map((item) => `<${item.href}>; rel="${item.rel}"`) | ||
| ) | ||
|
|
||
| const htmlResponse = ` | ||
| <!DOCTYPE html> | ||
| <html> | ||
| <head> | ||
| ${links | ||
| .map((item) => html`<link rel="${item.rel}" href="${item.href}" />`) | ||
| .join('')} | ||
| </head> | ||
| <body> | ||
| To subscribe to our topic, make a POST request to this endpoint with the valid hub payload. | ||
| The link to hub is also included in the head and headers. | ||
| </body> | ||
| </html> | ||
| ` | ||
| return res.status(200).send(htmlResponse) | ||
| } catch (error) { | ||
| logger.error(error.message) | ||
| return res.status(500).send(error.message) | ||
| } | ||
| } |
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